They knew with certainty that I came from you, and they believed that you sent me.

I'm guessing that this is a translation issue, but I'm curious to hear expert opinion. Here Jesus is praying about "those you have given me" (verse 6 & 9), by which I presume He means His disciples or all Christians.

Welcome to Biblical Hermeneutics.SE! I don't disagree with anything you say here, but I think the text is a bit more complicated than Jesus putting people in the best light. I wonder if I could convince you to expand on this answer a bit. It sounds like you are attributing wishful thinking to Jesus, but I'm sure he was well aware about the level of doubt his followers were currently experiencing. There's the seed of an answer here, but it would help if you filled in our picture of the text. Thanks!
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Jon Ericson♦May 1 '12 at 16:51